The watchdog timer is a technique widely applied in the microprocessor control unit (MCU). Generally, the MCU includes an oscillator (OSC) with an intrinsic free run function, a counter that is able to be cleared by software and a circuit for generating a reset signal when the counter overflows. The oscillator provides a clock source for the counter. The MCU is regarded as malfunctioning if the counter is unable to be cleared within a specific time period. In such situation, the reset signal is correspondingly generated by the circuit for restoring the MCU to a normal operation.
The temperature compensation technique is extensively used in the measurement application for modifying the effect of temperature variation on the measuring result. For the temperature compensation, the component sensitive to temperature variation is often used with the cooperation of the analog-to-digital converter (ADC) inside the MCU. Preferably, the component sensitive to temperature variation described above is a thermistor.
For the conventional temperature compensation, an additional component is required for serving as the temperature sensor and an ADC channel has to be occupied, which is not economical in cost. Therefore, if the circuits and components essentially implicit in the MCU can be employed to accomplish the temperature compensation, without affecting their original functions, the cost thereof can be significantly saved.
Therefore, the present invention provides a novel circuit and method for the temperature compensation. The particular design in the present invention not only solves the problems described above, but is also easy to be implemented. Thus, the present invention has the utility for the industry.